This comedy, inspired by the popular light comic novel by Richard Gordon, was the brainchild of Betty Box, described by James Mason as "the most sensible and hardworking producer in the British industry". Her belief in the project's potential was well founded: the film was a massive box-office hit, which spawned numerous sequels. "In six weeks at the Odeon Leicester Square, it more or less paid for itself," Box later recalled.

Undeterred by the novel's anecdotal construction, or the concerns of executive producer Earl St. John, who reported back from a board meeting that "they don't like doing hospital films, films about illness", Box enlisted writer Nicholas Phipps, about whose screenplay Box later commented "there wasn't a great deal of the book in it, except for the characters".

The result was a gentle comedy, reliant on carefully paced character development and interaction rather than the contrived one-liners or the innuendo of the later Carry On series. Strong performances hold together a series of episodic set pieces that cosily evoke various aspects of student life. Characterisations remain plausible throughout, and are not obviously compromised for the sake of a joke. Importantly, an air of medical authenticity, and the gravitas of the hospital as an institution, is maintained (no doubt aided by the constant on-set presence of two doctors acting as advisors).

Dirk Bogarde gives a controlled and genial performance as quiet, self-effacing student Simon Sparrow. Moving away from the kind of roles he had predominantly been seen in, he effectively launched his career as 'the idol of the Odeons' in the process. He later recalled: "the studio believed I could only play spivs and cockneys, but Betty and Ralph [Thomas, the director] put me in tweeds and let me speak in my own voice, and the rest was history."

Among a capable supporting cast, James Robertson Justice stands out, giving a brilliant, memorable and genuinely funny performance as Sir Lancelot Spratt, the fiery, abrasive but good-hearted surgeon. A last minute replacement for Robert Morley (who was too expensive), Justice is completely convincing, and steals every scene in which he appears.

In hindsight, it is perhaps difficult to determine precisely the reasons for the film's huge popularity with British audiences, but Betty Box obviously knew what she was doing. She later recalled: "I think it was the youthful gaiety of it that made it so popular, and it was something everybody knows about - doctors, hospitals, illness."